Zinc oxide sintered body, and preparation process and use thereof

Abstract

An electroconductive zinc oxide sintered body composed of sintered particles fusion-bonded in the grain boundaries thereof; which has a sintered density of from 5 to 5.5 g/cm 3 ; and which does not substantially contain closed cells isolated from the outside in the interior of the sintered body. The electroconductive zinc oxide sintered body is prepared by sintering a mixture of an oxide of an element having a positive valency of at least 3 and zinc oxide in the presence of water at a temperature of at least 1,300° C. The electroconductive zinc oxide sintered body is used as a sputtering target for the preparation of a low resistance, transparent electroconductive film.

We claim: 
     
       1. A process for the preparation of an electroconductive zinc oxide sintered body, which comprises the steps of: mixing powdery zinc oxide and a powdery hydrate of at least one oxide of an element having a positive valency of at least 3, and   sintering the mixture at a temperature of at least 1,300° C.;   said element being selected from the group consisting of Sc and Y of groups IIIB of the Periodic Table, B, Al, Ga, In and Tl of the group IIIA, Ti, Zr, Hf and Th of the group IVB, C, Si, Ge, Sn and Pb of the group IVA, V, Nb, Ta and Pa of the group VB, As, Sb and Bi of the group VA, Cr, Mo, W and U of the group VIB, Se, Te and Po of the group VIA, Mn, Tc and Re of the group VIIB, Fe, Co, Ni, Ru, Rh, Pd, OS, Ir and Pt of the group VIII, lanthanide elements, and actinide elements, and the amount of said element being from 0.1 to 20 atomic % based on the amount of the zinc of the zinc oxide.   
     
     
       2. The process according to claim 1, wherein the amount of the element having a positive valency of at least 3 is from 0.5 to 5 atomic % based on the amount of the zinc of the zinc oxide. 
     
     
       3. The process according to claim 1, wherein the mixture of the oxide of the element having a positive valency of at least 3 and the zinc oxide is first molded, and the resulting molded mixture is then subjected to sintering. 
     
     
       4. The process according to claim 1, wherein the sintering is carried out at a temperature of from 1,400° C. to 1,500° C. for from 5 to 20 hours. 
     
     
       5. The process according to claim 1, wherein the sintering is carried out at a temperature of from 1,450° C. to 1,500° C.